Cache for compiler functions, declared external functions and constants.
Get the numbawrapper.AutojitFunctionCache that does a quick lookup for the cached case.
Get a compiled function in the the function cache. The function must not be an external function.
For an external function, is_registered() must return False.
Check if a function is registered to the FunctionCache instance.
Register a function to the FunctionCache.
It is necessary before calling compile_function().
Keep an object alive for the lifetime of the translated unit.
This is a HACK. Make live objects part of the function-cache
NOTE: py_func may be None, so we can’t make it a function attribute